Some digital cameras employing an image sensor, e.g. a CCD or C-MOS or the like, as an image sensing device, incorporate a white balance adjusting device. Human eyes have an adaptability to perceive a white object as white even if the color temperature of an illuminating light source changes. However, in digital cameras, because it is necessary to adjust and correct data from the image sensing device in accordance with the color temperature of a light source by using software, normally a white balance adjusting device is included.
White balance adjusting methods include: a method that performs white balance control based on data obtained from an image sensing device, a method that performs white balance control based on data obtained from a colorimetric sensor which detects a color temperature of a light source illuminating an object, and a combination of the aforementioned methods.
However, despite using the above-described white balance adjusting device, there are cases depending on image sensing conditions that excellent white balance adjustment cannot be performed. In view of this, Japanese Patent Application Laid-Open No. 1-221994 proposes a white balance bracketing function for obtaining an image having an excellent white balance by recording plural numbers of images, processed with plural white balance correction values which are obtained by shifting the correction value.
While white balance bracketing is a type of image processing, there is an image sensing apparatus having an automatic exposure (AE) bracketing function for performing exposure control, which is a largely different type of processing from the white balance bracketing. Conventionally, the AE bracketing function has been employed by still cameras using silver chloride films. According to an AE bracketing image sensing operation, in a case where it is difficult to determine an appropriate exposure, e.g., a case of sensing an image at sundown or a case where a highly reflective object partially exists in an image, plural frames of one scene are sequentially sensed while changing the set shutter speed and/or f value by a predetermined amount. Then, a frame having the most appropriate exposure is selected from the plural images. Utilizing such image sensing apparatus having the AE bracketing function achieves an advantage in that an image can be sensed automatically with an appropriate exposure or a desired exposure intended by the user, without missing a perfect moment for an excellent image.
However, in the aforementioned image sensing operation using various bracketing functions, image sensing must be performed for plural frames to sense the image while shifting the correction value to the + side and − side by a predetermined amount relative to a reference value. Assume a case of sensing an image by shifting the correction value 2 levels to the + side and 2 levels to the − side relative to a reference value. In this case, image sensing must be performed five times, with the correction value respectively set at −2, −1, 0 (no correction), 1, and 2 (these values conceptually express the correction value including a reference value).
If a camera user feels that it is difficult to properly correct the color temperature using automatic white balance correction and properly detect appropriate exposure using automatic exposure (AE) detection and sets both of the WB and AE bracketing functions, an extremely large number of frames must be sensed. In this case, the user may be unable to determine which image is obtained with what type of correction.
For instance, in a case of performing five times of image sensing with the AE bracketing function in addition to five times of image sensing with the white balance bracketing function as mentioned above, 25 frames of images must be sensed, processed, and/or recorded. This not only wastes the image sensing time, but also requires a large amount of memory capacity to store the sensed images. Further, if another bracketing function is additionally set, the time required for image sensing and the amount of image data increase immensely.
Furthermore, even if a large amount of images are obtained in this manner, the necessary image having an appropriate color and exposure is only one.
Moreover, with regard to an AE bracketing image sensing operation, there has been a camera capable of plural bracketing settings, which prohibits simultaneous setting of different types of factors related to exposure, as proposed by Japanese Patent Application Laid-Open No. 8-29828. However, it has been unable to solve problems related to operability of image processing function setting, e.g., white balance correction or the like, which is necessary for a digital camera.